In an attempt to further elucidate the basic mechanism of aflatoxin action and to determine whether certain dietary modifications might alter aflatoxin toxicity we propose to study the effects of varying levels of 2 different fats stripped of vitamin E, one primarily saturated (lard) and one primarily unsaturated (corn oil) with and without the addition of vitamin E, and aflatoxin toxicity in rats fed an otherwise nutritionally adequate diet. These studies are conducted in rats that have been exposed to aflatoxin for a short period of time and then maintained on control diets for up to 1 year to allow for tumor formation. Histopathology of tissues as well as several biochemical analyses will be performed, such as cholesterol and fatty acid biosyntheses, cholesterol and total lipid levels in liver, liver tumors and plasma, fatty acid patterns in lipid fractions from these tissues and vitamin E levels in plasma.